Transbronchial needle aspiration (TBNA) is an accepted method for obtaining tissue from mediastinal and hilar locations within the thorax. Linear array endobronchial ultrasound (EBUS) has improved the diagnostic yield of TBNA to greater than 90% for solid tumors,1 though the yield for hematologic malignancies and benign diseases in which tissue architecture is preferred is lower.2,3 Although success using EBUS-TBNA for the diagnosis of lymphoma has been reported,4 the gold standard for diagnosing these conditions remains surgical biopsy by mediastinoscopy for mediastinal abnormalities and video-assisted thoracic surgery for abnormalities at hilar locations.5
Bronchoscopic forceps biopsy of subcarinal lymph node stations has been described earlier, using different techniques, by Prakash6 and Oki et al7; Herth et al8 were the first to describe this process using EBUS guidance. In this study, we report our experience in 12 patients who underwent EBUS-guided miniforceps biopsy of mediastinal and hilar lymph node stations in a bronchoscopy suite under conscious sedation.
MATERIALS AND METHODS
After approval by the Institutional Review Board, linear array EBUS cases between September 1, 2008, and January 31, 2009, in which TBNA and EBUS-guided miniforceps biopsy were performed were reviewed. The decision to perform miniforceps biopsies was determined by a clinical history or radiographic appearance suggestive of granulomatous disease, hematologic malignancy, or other diagnoses in which increased amounts of tissue specimen were desirable. The targeted lymph node stations included paratracheal, subcarinal, and hilar regions.
TBNA was always performed before miniforceps biopsy, and all procedures were performed in a bronchoscopy suite under conscious sedation without an endotracheal tube in place.
EBUS-TBNA was performed in standard fashion using a linear array EBUS bronchoscope (Olympus XBF-UC260F-OL8) and a 22-gauge aspiration needle. Four to 6 needle aspirations were taken from each lymph node station, and the highest stage station was always targeted first. On-site cytotechnologists prepared each specimen after needle aspiration, and specimens were then reviewed by cytopathologists.
EBUS-guided Miniforceps Biopsy
Once EBUS-guided TBNA was completed at all stations, the linear array EBUS bronchoscope was positioned at a targeted lymph node station. If more than 1 station was abnormal (ie, paratracheal and subcarinal), the subcarinal station was targeted for miniforceps biopsy first.
The targeted lesion was identified using EBUS at the desired station. Once an EBUS image was obtained, a 22-gauge aspiration needle was used to puncture the airway mucosa and access the target lesion using the same technique as that for EBUS-TBNA. With the EBUS bronchoscope in the same position, the TBNA needle was withdrawn, and 1.0-mm miniforceps (Boston Scientific M00546270) were passed through the airway mucosa into the target lesion under continuous EBUS guidance (Fig. 1). The EBUS image was primarily used to direct the forceps through the airway mucosa and into the target lesion. Direct visualization of the TBNA puncture site through the EBUS bronchoscope was not mandatory, and was seldom used. Instead, attention was focused on maintaining a steady and reproducible EBUS image of the target lesion, which facilitated pushing the miniforceps through the airway mucosa into the target lesion in the same tract as that made by the TBNA needle. Once this tract was established, the miniforceps were easily advanced into the target lesion using very little forward pressure. Once inside the target lesion, the miniforceps were opened and biopsy specimens were taken, all under continuous EBUS surveillance (Figs. 2, 3). A minimum of 3 miniforceps biopsy specimens were obtained from each targeted lymph node station using this technique.
Bronchoscopic miniforceps biopsy was performed at 15 total lymph node stations in 12 patients. A definitive diagnosis was obtained in 14 out of 15 miniforceps biopsy samplings (93%) and a diagnosis was made by miniforceps biopsy in 12 of 12 patients.
EBUS-TBNA was performed at 20 total lymph node stations in the same 12 patients and was diagnostic in 8 of 12 patients (67%). In the 4 cases in which TBNA was nondiagnostic, bronchoscopic miniforceps biopsy successfully yielded a diagnosis. In these 4 patients, TBNA was performed at 1 site in patient 1, 2 sites in patient 6, 2 sites in patient 10, and 1 site in patient 11; all passes on TBNA from these sites were nondiagnostic, showing benign bronchial cells, necrotic tissue, lymphatic tissue, or atypical cells that were inadequate for a definitive diagnosis. Table 1 outlines miniforceps biopsy locations and specific TBNA and miniforceps biopsy diagnoses.
No complications occurred as a direct result of the procedure or the conscious sedation administered during the procedure. All patients received postprocedure chest radiographs within 1 hour of the procedure and follow-up correspondence with an Interventional Pulmonary attending within the week to discuss biopsy results.
Linear array EBUS-guided TBNA has significantly impacted the evaluation of mediastinal and hilar abnormalities of the chest. The diagnostic accuracy of this procedure for solid tumors is well above 90%, though its utility is not as appreciable for diagnosing hematologic malignancies such as lymphoma or for benign conditions such as granulomatous inflammation. In addition, the negative predictive value of EBUS-TBNA for excluding malignancy is not robust,9 such that in most clinical practice, a negative TBNA result in a patient with a high clinical suspicion of malignancy ultimately is referred for a surgical biopsy, either by mediastinoscopy or by thoracoscopic surgery, depending on the involved lymph node station.
In this feasibility study, we attempted to address the specific issue of larger tissue biopsies and preservation of tissue architecture using a technique of transbronchial miniforceps biopsy of mediastinal and hilar lymph node stations under continuous EBUS guidance. Our results in 12 patients showed a definitive diagnosis in 12 of 12 patients, despite a TBNA diagnosis in 8 of 12 patients. For granulomatous disease, TBNA was diagnostic in 5 of 8 cases (63%), a figure lower than that reported by Garwood et al,10 though higher than reported elsewhere. In addition, TBNA was nondiagnostic in 1 case of lymphoma in this study, whereas miniforceps biopsy was positive.
The concept of transbronchial forceps biopsy of mediastinal lesions is not novel, and has been described earlier. Prakash first performed subcarinal biopsies through a small incision in the airway mucosa; Oki et al subsequently described this procedure using miniforceps biopsy and fluoroscopic guidance. Herth et al most recently described it using EBUS guidance for miniforceps biopsy of subcarinal lesions. Their procedure was performed under general anesthesia using rigid bronchoscopy. A puncture site was made using a 19-gauge needle, and miniforceps were subsequently directed into the subcarinal lesion through this puncture site. Biopsy specimens were then taken under EBUS guidance.
The technique that we describe differs in the following ways. (1) Our procedure was performed under conscious sedation in an outpatient bronchoscopy suite. (2) This procedure was performed using the linear array EBUS bronchoscope only. Puncture of the airway mucosa using a 19-gauge needle requires identifying the lesion first using EBUS, withdrawing the EBUS scope and inserting a flexible bronchoscope with a working channel that accommodates a 19-gauge needle, puncturing the airway mucosa, removing the flexible bronchoscope, and then reintroducing the EBUS bronchoscope and finding the puncture site through which to insert the miniforceps. We had attempted this same technique in the past and found it difficult to perform in patients under conscious sedation. The technique that we describe is performed with the linear array EBUS scope and does not involve exchanging bronchoscopes, thereby decreasing procedure time and complexity. (3) Our technique was used to sample paratracheal and hilar lymph node stations, in addition to subcarinal lesions. To our knowledge, miniforceps biopsy has not been reported at these locations. The ability to sample hilar lesions is particularly appealing because these stations typically require video-assisted thoracic surgery to obtain adequate tissue specimens, and are not amenable to biopsy by mediastinoscopy.
Our study has several limitations, the most notable of which is its small sample size. This review was conducted to assess the feasibility of such a technique, and while it was diagnostic in all 12 patients, a larger, ongoing prospective study is being undertaken to truly establish efficacy.
Only 1 of 12 patients in this population had lymphoma, a diagnosis for which the technique of miniforceps biopsy may offer a significant advantage over EBUS-TBNA. Herth et al reported a diagnostic yield of 81% for lymphoma using miniforceps, compared with 35% for TBNA.
In conclusion, this study describes a new technique using miniforceps for the biopsy of mediastinal and hilar lymph node stations using continuous EBUS guidance performed under conscious sedation. We believe that this technique may expand the application of EBUS and have significant clinical impact on the diagnosis of centrally located chest abnormalities, potentially obviating the need for surgical procedures in selected patients.
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